Fish Tissue

In nearly all cases, the fish in Iowa are safe to eat. The cleaning and or preparation of the meal cause most the problems regarding taste or color of fish meant for consumption. As with all other living creatures, fish are susceptible to diseases, parasites, and other naturally occurring conditions in the water. If you suspect your fish is affected by any of these conditions, it should NOT be eaten.

The table below lists the current fish consumption advisories. Fish tissue sampling methodologies and strategies can be found below the advisory table.

Fish Consumption Advisories

Monitoring for Pollutants in Fish Tissue

Routine fish tissue monitoring is conducted in Iowa as part of three long-term programs: (1) Iowa Fish Tissue Monitoring Program (IFTMP), (2) water quality studies of the Des Moines River near the Saylorville and Red Rock reservoirs, and (3) water quality studies of the Iowa River near Coralville Reservoir. Beginning in 1977, annual fish collection and analysis activities in Iowa have been conducted by DNR as a joint effort between the Fisheries and Water Quality bureaus. Annual fish contaminant monitoring at three of Iowa's federal flood control reservoirs is sponsored by the U.S. Army Corps of Engineers (Rock Island District). This monitoring is conducted by Iowa State University (Saylorville and Red Rock reservoirs) and by the University of Iowa (Coralville Reservoir).

Iowa Fish Tissue Monitoring Program (IFTMP)

Introduction:

To supplement other environmental monitoring programs and to protect the health of people consuming fish from waters within this state, the state of Iowa conducts fish tissue monitoring. Since 1977, the Iowa Department of Natural Resources (DNR and the State Hygienic Laboratory (SHL) have cooperatively conducted annual statewide collections and analyses of fish for toxic contaminants. From 1983 to 2013, this monitoring effort was known as the Regional Ambient Fish Tissue Monitoring Program (RAFT). Beginning in 2014, the only statewide fish contaminant-monitoring program in Iowa was changed to the Iowa Fish Tissue Monitoring Program (IFTMP). The IFTMP is administered by DNR and the analyses are completed at the SHL. Historically, the data generated from the IFTMP have enabled DNR to document temporal changes in contaminant levels and to identify Iowa lakes and rivers where high levels of contaminants in fish potentially threaten the health of fish-consuming Iowans (see 2006 DNR Fish Tissue Monitoring Fact Sheet). The IFTMP incorporates five different types of monitoring sites: 1) status, 2) follow-up, 3) trend, 4) turtle, and 5) random.

Status monitoring:

The majority of IFTMP sites are sampled to determine whether the waterbodies meet the “fish consumption” portion of the fishable goal of the federal Clean Water Act. In other words, these sites are used to screen for contamination problems and to determine the water quality "status" of the waterbodies. Analyses for chlordane, DDE, dieldrin, PCBs, and mercury are conducted on samples of omnivorous bottom-dwelling fish and mercury analysis is conducted on carnivorous predator fish. Most status sites on rivers and lakes have either never been sampled or have not been sampled within the last five years (rivers) or 10 years (lakes). Staff of the DNR divisions of Environmental Services and Conservation and Recreation collaborate to select the status sites. Status monitoring occurs on most types of Iowa waterbodies (interior rivers, border rivers, and man-made and natural lakes) in both rural and urban areas. Lakes and river reaches known to support considerable recreational fishing receive highest priority, but DNR attempts to sample all lakes and river reaches designated in the Iowa Water Quality Standards for recreational fishing. Approximately one-third to one-half of IFTMP status sites are located on lakes; the remaining sites are either located on interior rivers or located on the border rivers (Mississippi, Missouri or Big Sioux rivers).

Follow-up Monitoring:

If the level of a contaminant in a fish tissue sample exceeds IDPH/DNR advisory trigger levels and/or DNR levels of concern, the IFTMP conducts follow-up monitoring to better define the levels of contaminants. For example, if status monitoring shows that contaminant levels in fish from a waterbody exceed IDPH/DNR advisory trigger levels, additional samples will be collected as part of follow-up monitoring for the next year's IFTMP. If follow-up monitoring confirms that levels of contamination exceed the advisory trigger levels for protection of human health, a fish consumption advisory is issued. If needed, DNR Fisheries Bureau will conduct follow-up monitoring separately from the IFTMP to verify high levels of contaminants or to better delineate lengths of river consumption advisories. These follow-up samples are collected before the annual IFTMP sampling and are also analyzed at SHL.

Trend monitoring:

In 1994, DNR identified sites that would be monitored at regular intervals to determine trends in levels of contamination. One composite sample of three to five Common Carp from each site is submitted for whole-fish analysis. Whole-fish samples are more likely to contain detectable levels of most contaminants than are fillet samples (edible portions) or tissue plugs. Examination of the trend monitoring results may help identify temporal changes in contaminant concentrations and may expose new contaminants entering the food chain. From 1994-2005, half of the trend sites were sampled on odd years and the other half were sampled in even years. Beginning in 2006, all 10 trend sites are sampled every other year. DNR added five trend sites in 2016 to bring the total to 15 trend sampling sites in Iowa.

Turtle Monitoring:

In 2009, DNR fisheries biologists collected snapping turtles from nine Iowa lakes as part of the annual fish tissue monitoring to better define contaminant levels in Iowa turtle populations. This monitoring used the left front shoulder muscle tissue from two or three turtles for the sample that was submitted for analysis following the same protocol used for fish. The snapping turtle monitoring continued in 2010 at four Iowa lakes, was suspended in 2011 and resumed in 2012. In 2013, softshell turtles were sampled in addition to the snapping turtles. Turtle sampling will continue to be part of the IFTMP for the foreseeable future.

Random Monitoring:

In 2006, based on recommendations in U.S. EPA’s RAFT workplan, Iowa began sampling random sites across the state as part of an effort to determine the current level of contaminants in fish tissue on a statewide basis. The 2006 sampling sites were selected from a previous random sampling project and data were collected only from large interior rivers. In 2007, the sampling sites were selected from a random list of smaller public lakes and ponds. Due to the fact that Iowa is no longer part of the RAFT program, the future of random sampling for Iowa fish contaminants is uncertain.

Annual fish tissue sampling reports are available online in Adobe PDF format:

• 2021 IFTMP Report
• 2020 IFTMP Report
• 2019 IFTMP Report
• Find Previous Reports at the State Library

Additional Fish Consumption Resources:

• Iowa Dept of Public Health - Health Issues Regarding Fish Consumption
• 2006 Fish Tissue Monitoring in Iowa fact sheet